The invention concerns an arrangement for rotatably supporting an element rotatable about an axis.
By way of example, such an element may be an operating or control wheel, a rotary control knob, a roller or the like component, more especially and by way of example for a fresh air intake nozzle for a vehicle.
One of the major problems encountered in a situation such as the production of fresh air intake nozzles for vehicles is that of reliably observing and maintaining the required torques and operating forces at the operating or control wheels, rotary control knobs, the guide plates of rolling units which are provided for guiding and deflecting the air flow into the vehicle, and so forth, in a temperature range of between xe2x88x9240xc2x0 C. and +100xc2x0 C. That wide temperature range involves variations in the dimensions of such elements, due to the temperatures acting thereon, and such dimensional variations influence the torques and operating forces required. That in turn means that the degree of constancy in the torques and operating forces concerned hitherto can leave something to be desired, when such a wide temperature range is taken into consideration.
An object of the present invention is to provide an arrangement for rotatably supporting an element rotatable about an axis, which is capable of affording at least substantially constant torques and operating forces within a wide temperature range of for example between xe2x88x9240xc2x0 C. and +100xc2x0 C.
Another object of the present invention is to provide an arrangement for rotatably supporting a rotatable control or operating element, which is so designed as to provide a compensating effect in regard to temperature-induced influences on the rotatable element.
Still another object of the present invention is to provide an arrangement for rotatably supporting a rotatable control or operating element, which while being of a simple structure provides for a uniform force needing to be applied to the element for rotation thereof.
In accordance with the principles of the present invention the foregoing and other objects are attained by an arrangement for rotatably supporting an element rotatable about an axis, for example a control or actuating wheel, a rotary control knob, a roller unit or the like, for example for a fresh air intake nozzle for a vehicle, wherein a casing of a generally plug-shaped configuration adapted to be fitted to a mounting portion, for example a part of a vehicle as referred to above, has an end portion and a peripherally extending flange thereon, which extends away from the end portion in the axial direction of the casing, providing a circular external peripheral surface to form a rotational mounting surface for the rotatable element. The flange defines therewithin a guide space and the flange has first and second diametrally mutually oppositely disposed holes therethrough. First and second braking members are disposed in the guide space and have braking portions which face diametrally away from each other and extend through respective ones of the holes in the flange. A spring member is operatively disposed between the first and second braking members and urges the braking members away from each other.
The braking portions can thus project radially outwardly beyond the external peripheral surface of the casing and come into engagement with a surface of the rotatable element to apply a braking effect thereto. The spring member between the two braking members can thus afford, independently of the temperature involved, a constant braking force and thus a constant torque which is independent of temperature or an operating force which is independent of temperature for actuating the element which is thus supported rotatably at the stationary immobile casing forming the axis of rotation for the element. All this has an advantageous effect in terms of operating comfort and convenience.
In a preferred feature of the invention, the transverse holes in the flange of the casing steplessly adjoin the end portion of the casing, because then the braking portions of the two braking members can be so designed and dimensioned as to afford the largest possible braking areas.
A further preferred feature of the invention provides that the transverse holes in the flange are of an internal cross-section which is adapted to the cross-section of the braking portions of the braking members. That provides for optimum guidance in terms of mobility of the braking members in the casing.
Another preferred feature of the arrangement according to the invention provides that each braking member has a guide and abutment portion which adjoins its braking portion and which is guided in the guide space of the casing. Besides reliable linearly movable guidance for the braking members, the guide and abutment portion also advantageously means that the braking members are arranged in the casing, in such a way that they can be reliably arranged therein and therefore cannot easily go missing.
A further preferred feature of the arrangement provides that the guide space in the casing has first and second mutually parallel and oppositely disposed guide surfaces at which the braking members are linearly movably guided with their guide and abutment portion. Such a configuration affords the advantage that the casing and the braking members are simple to produce and the braking members can be easily disposed in the casing.
In a further preferred feature the flange of the casing of the arrangement of the invention has a peripherally extending collar, at the upper edge of the casing flange which is in axially opposite relationship to the end portion of the casing. That makes it possible for the arrangement to be accurately fitted in position in a simple and time-saving manner. When fitting the arrangement, the collar forms a support configuration which permits precisely correct positioning of the casing and thus the braking members, in relation to the element which is to be supported and braked thereby, in a simple procedure.
Still another preferred feature of the invention provides at least first and second resilient snap members integrally disposed on the collar and projecting in the same direction away therefrom. That provides for ease of fitting and fixing the arrangement according to the invention to an appropriate part of a vehicle.
Further objects, features and advantages of the invention will be apparent from the description hereinafter of a preferred embodiment.